1. Field of the Invention
A particularly large, stationary, modular, open framework type of static structure for supporting apparatuses to perform desired operations, such as sorting and classifying mine rock for use as aggregate or other material.
2. Discussion of the Related Art
U.S. Pat. No. 5,634,716, issued Jun. 3, 1997 to Westall et al., discloses a portable PVC resin blending system mounted in a steel silo having multiple level therein. This patent discloses a portable batch blending system which, by reducing the cross-sectional size of the blending system to a limited diameter cylinder, can be transported across roads, for example, from the plant where it is manufactured to the field where it is put in use. The unit can then be readily relocated without disassembling the system.
U.S. Pat. No. 5,433,575, issued Jul. 18, 1995 to Milstead, is assigned to assignee common with the present invention. This patent shows a method of erecting a relatively small, portable asphalt production plant. Upper and lower subassemblies of the plant are transported to a worksite on a portable frame towed by a tractor. A portable plant of this type can be transported from one worksite to another by a vehicle.
U.S. Pat. No. 2,150,717, issued Mar. 14, 1939 to Jaxon, discloses an apparatus for screening and loading coal.
U.S. Pat. No. 3,909,401, issued Sep. 30, 1975 to Thompson, shows a relatively small portable screening tower mounted on a wheel vehicle having a first framework connected to the ground engaging means, and a second framework movably vertically with respect to the first framework and having a material screening facility mounted thereon.
The present invention provides a particularly large and stationary modular aggregate processing tower structure and method of manufacturing, assembling and installing the structure. The structure of the present invention may be 100 feet in height and 40 to 60 feet in length. The invention contemplates producing such a tower in a number of layers of weldment modules, for example, five layers of modules, the modules each being substantially completely assembled in the plant. That is to say, to the extent possible, assembling the various components within the individual modules is done at the plant. The various components to be inserted in the modules may consist of, for example, aggregate classifiers, screens, collecting chutes, blending units, stairways and walkways. In this manner, the majority of the manufacturing and assembly can be done in the plant and thus avoid the necessity of such manufacturing and assembly to be done at the field erection site.
The preassembled modules are then transported to a field site where they are then aligned with one another by interengaging parts and then secured together as by bolting them into a permanent rigid plant. In one form of the invention the stacked modules receive aggregate product at its uppermost module by means of a conveyor elevator, and the aggregate is processed by screening, blending and sizing into aggregate product as it moves downwardly by gravity through the modules and their processing equipment. The final collection of product is made at various levels.
The above method includes providing a multiple deck screen in the uppermost module and which screen is inclined downwardly for passing aggregate product over the screen and into collecting chutes beneath this multiple deck screen. The product is then discharged out of the chutes as four different size products.
Still a more limited aspect of the invention relates to a method of the above type in which a screening tower is provided having five layers of weldment modules, the modules being fabricated in the factory and preassembled with certain aggregate processing equipment, chutes and gates internal within the module. The five layers of preassembled modules are then transported by huge tractor-trailers, for example, and/or by rail or ships to the field quarry or the like where they are aligned with one another by means of interengaging parts and then rigidly secured together. In one form, the fifth, top module receives the aggregate product from a conveyor or the like and the product then moves downwardly by gravity through the stacked modules and is screened, blended and sized as it moves through appropriate screens, chutes, blenders and gates within the modules. The product is collected in various classifications at the various levels.
A further aspect of the invention relates to a method of the above type in which the lower layers of modules are assembled in stacked relationship and then a large double screen vibrator is inserted downwardly into the lower layers of modules, for example, the second and third layers, and then the vibrator is secured therein. Then the upper layers of modules, for example, the fourth and fifth layers of modules, are assembled thereon and rigidly secured in place.
The invention also provides a large stationary modular aggregate processing screening tower having weldment modules preassembled, having aggregate processing equipment internally within the modules. The preassembled modules are guided into alignment and are then secured together. The stacked modules are adapted to receive aggregate product at the top module and the product is screened and sized as it moves downwardly by gravity through the lower modules.
The invention provides a large stationary modular aggregate processing screening tower having five layers of weldment modules with aggregate processing equipment and accessories internal within them. The layers of modules have interengaging guiding means for aligning them vertically with respect to one another and are then bolted together. The arrangement is such that the layers of modules receive aggregate product at the top fifth layer module and the product is processed by screening, sizing, blending and/or classifying as it moves by gravity downwardly through the layers of weldment modules. The product is collected at various levels in their proper classifications.
Still another object of the present invention relates to providing a modular screening tower having a double screen vibrator having its two screens positioned one above the other and the lower discharge end of the screens have separate outlet conduits for discharging the screened product. A hot air conduit is in communication with the vibrator adjacent the discharge end of the lower of said screens. This conduit directs hot air into the lower end of the vibrator where the air rises within the vibrator to dry the sand product therein. An oil or gas heater is in communication with the heat conduit for supplying hot air to the vibrator.
The invention furthermore provides the vibrator of the above type in which a reversible screw conveyor is located below the two outlet conduits of the vibrator for receiving product and conveying the product selectively to two separate receptacles.
The invention furthermore provides a primary aggregate handling plant having several modules arranged in vertical alignment and others being laterally offset in working relationship with others to provide continuous processing of aggregate through all of them.
Another object of the present invention is to provide a double screen vibrator and air heater for drying the sand and thereby making concrete sand without the use of water to wash the fine 200-mesh dust off of the coarser material. Hot air pulled through the lower screen deck dries the material sufficiently to suck off the minus 200-mesh material to thereby produce clean, dry product without the use of water.
Another object of the present invention is to provide a double screen vibrator having two stationary vertical side walls with upper and lower screens positioned one above the other and mounted between the side walls and positioned at a downwardly inclined angle. The vibrator has a lower discharge end with outlet conduits for discharging screened product from the screens. High frequency electric vibrators are connected with the screens for vibrating the screens at a frequency of 3000 to 5000 rpm. A hot air heat conduit is in communication with the vibrator adjacent the discharge end of the lower of the screens and for directing hot air into the vibrator where the air rises within the vibrator to dry the product such as sand therein. A heater is in communication with the heat conduit for supplying hot air to the conduit and over the sand to reduce the moisture content of the fine sand to 2% to 3% and remove the fine 200-mesh particles of sand to achieve production of concrete sand in a dry application.
These and other objects and advantages of the present invention will appear hereinafter as this disclosure progresses.